Bug query result cache key is redundant

[vuongxuongminh]

Currently, when using multi varies, query result cache key will be redundant on the same query because loop on the map not guaranteed key position for each request.

gbox/caching_plan.go

Lines 245 to 274 in 998a7f2

	for name := range plan.VaryNames {
	vary, ok := p.caching.Varies[name]
	if !ok {
	return "", fmt.Errorf("setting of vary %s does not exist in varies list given", vary)
	}
	for name := range vary.Headers {
	buffString := fmt.Sprintf("header:%s=%s;", name, r.Header.Get(name))
	if _, err := hash.Write([]byte(buffString)); err != nil {
	return "", err
	}
	}
	for name := range vary.Cookies {
	var value string
	cookie, err := r.Cookie(name)
	if err == nil {
	value = cookie.Value
	}
	buffString := fmt.Sprintf("cookie:%s=%s;", cookie, value)
	if _, err := hash.Write([]byte(buffString)); err != nil {
	return "", err
	}
	}
	}

[vuongxuongminh]

Resolved by #32